1. Field of the Invention
The present invention relates to the technology of material measures for use in evaluating the performance of a measuring instrument for measuring surface texture.
2. Description of the Related Art
A means for evaluating the performance of a measuring instrument for measuring surface texture can be a method of using material measures whose surfaces have a plurality of grooves.
There are various types of material measures, but the material measures whose surfaces have grooves having the same shapes in a predetermined direction as described in Standard Number JISB0659-1 “Geometrical Product Specifications (GPS)—Surface Texture Profile method; Measurement standards—Part 1: Material Measures” have become widespread lately.
The groove shapes of material measures are in many cases simple from the viewpoint of easy evaluation, processing, etc. For example, material measures 100 having the cross-sectional shapes of grooves 101 exemplified in FIGS. 1A through 1D, that is, a sine wave shape (refer to FIG. 1A), a triangle shape (refer to FIG. 1B), a trapezoid shape (FIG. 1C), and an arc shape (refer to FIG. 1D), are known.
The performance of a measuring instrument is evaluated by whether or not the shape of the groove 101 of the material measure 100 can be appropriately measured. To be more concrete, for example, there is a method of evaluating the performance of a measuring instrument by checking the change in measurement accuracy of the depth (amplitude) of a groove to the width (cycle) of the groove (hereinafter referred to as a response characteristic) described in the Theses of the Lectures of the Academic Lecture Meeting in Spring 2009 of the Institute of Precision Industry, p. 495-496 (by Akihiro Fujii and Kazuhisa Yanagi “A study on response properties of surface texture measuring instruments in terms of surface wavelengths”.
When the response characteristic of a measuring instrument is checked using a material measure formed by arranging the grooves of the same shape on its surface to evaluate the performance of the measuring instrument, for example, a plurality of material measures (material measures 102, 103, and 104) having equal depths (depth D) and different widths (widths W1, W2, and W3) of grooves as exemplified in FIGS. 2A through 2F are prepared and measured respectively.
In this case, if the cross-section of a groove is triangle-shaped as exemplified in FIGS. 3A through 3B, the inclination angle of the groove whose cross-section is triangle-shaped changes with the change of the width of the groove. In FIGS. 3A and 3B, the inclination angles of the grooves change from the angle θ1 to the angle θ2. In addition, as exemplified in FIGS. 4A and 4B, if the cross-section of a groove is sine-wave-shaped, the maximum inclination angle of the groove whose cross-section is sine-wave-shaped changes. In FIGS. 4A and 4B, the maximum inclination angles of the grooves change from the angle θ3 to the angle θ4.